Icterid

 ( Birds Of The Americas ) 

Icterids are variable in size, and often display considerable sexual dimorphism, with brighter coloration and greater size in males being typical. While such dimorphism is widely known in passerines, the sexual dimorphism by size is uniquely extreme in icterids. For example, the male great-tailed grackle is 60% heavier than the female. The smallest icterid species is the orchard oriole, in which the female averages 15 cm in length (6 in) and in weight, while the largest is the Amazonian oropendola, the male of which measures and weighs about . This variation is greater than in any other passerine family (unless the kinglet calyptura belongs with the , which would then have greater variation). One unusual morphological adaptation shared by the icterids is gaping, where the skull is configured to allow them to open their beak strongly rather than passively, allowing them to force open gaps to obtain otherwise hidden food. Most icterids have rounded tails and lack rictal bristles. They have nine primary feathers and are placed among the nine-primaried oscines.

Icterids have adapted to taking a wide range of foods. Oropendolas and caciques use their gaping motion to open the skins of fruit to obtain the soft insides, and have long bills adapted to the process. Others such as cowbirds and the bobolink have shorter, stubbier beak for crushing seeds. The Jamaican blackbird uses its bill to pry amongst tree bark and , and has adopted the evolutionary ecological niche filled elsewhere in the Neotropics by . Orioles drink nectar.

The nesting habits of these birds are also variable, including pendulous woven bird nest in the oropendolas and orioles. Many icterids are bird colony, nesting in colonies of up to 100,000 birds. Some cowbird species engage in brood parasite; females lay their eggs in the nests of other species, in a similar fashion to some .

Some species of icterid have become agricultural pests; for example, red-winged blackbirds in the United States are considered the worst vertebrate pests on some crops, such as rice.Dolbeer, R & S Ickes (1994) "Red-winged Blackbird feeding preferences and response to wild rice treated with Portland cement or plaster" Vertebrate Pest Conference Proceedings collection Proceedings of the Sixteenth Vertebrate Pest Conference (1994) (W.S. Halverson& A.C. Crabb, Eds.) Univ. of Calif.:Davis. The cost of controlling blackbirds in California was $30 per acre in 1994. Not all species have been as successful, and a number of species are threatened with extinction. These include insular forms such as the Jamaican blackbird, yellow-shouldered blackbird, and St Lucia oriole, all threatened by habitat loss; and the tricolored blackbird of California, which is threatened by habitat loss and destruction of nests.

A phylogenetic analysis of the passerine families by Carl Oliveros and collaborators published in 2019 found that the family Icteridae was sister taxon to the family Icteriidae (containing the yellow breasted chat) and together these two families formed a clade that was sister to the New World warbler family Parulidae.

The genus level cladogram shown below is based on a molecular phylogenetic study by Alexis Powell and collaborators that was published in 2014. The study compared mitochondrial gene sequences. The Subfamily are those that were proposed in 2016 by Van Remsen and collaborators. The numbers of species are taken from the list maintained by Frank Gill, Pamela Rasmussen and David Donsker on behalf of the International Ornithological Committee (IOC).

Prehistoric icterid genera that have been described from Pleistocene fossil remains are Pandanaris from Rancho La Brea and Pyelorhamphus from Shelter Cave.

• New World Blackbirds (Icteridae) - videos, photos and sounds at the Internet Bird Collection
• Icteridae - Tree of Life Web Project